This program is concerned with factors which may influence sleep-related respiratory depression in kittens, particularly forms of sleep apnea and hypoxic hypoventilation. Our first year goals included: 1. development of apparatus; 2. study of interaction of temperature and hypoxia; 3. implementation of the training program for Dr. McGinty. Kittens derived from a laboratory breeding colony were surgically prepared with chronic electrodes and after recovery from surgery, studied for 5 days, in a temperature controlled chamber. Initial studies were designed to investigate the effects of normal and elevated ambient temperature and hypoxia on respiratory patterns, sleep state patterns, and body temperature. Two kittens exhibited cardiorespiratory failure during treatment and were compared with the remaining surviving kittens and previously gathered normative data. The effect of elevated ambient temperature increased the percentage of AS in surviving kittens while failure kittens did not show a similar adaptation. Surviving kittens exhibited a significant increase in percent QS and a depression of percent AS during the hypoxic condition. Increased ambient temperature and hypoxia elevated the percentage of AS in surviving kittens above baseline levels. Failure kittens exhibited almost no AS. Data suggest that the combination of increased temperature and hypoxia in some kittens facilitates the occurrence of AS compared to hypoxia alone, thus providing the kitten with protection against respiratory failure.